Electrical distribution system



Nbv. 12, 1929. .1. WEINBERGER 1,735,143

ELECTRICAL DISTRIBUTION SYSTEM Filed Au 17, 1923 JUUUS WEINBERGER 3513 hi elf 97m Patented Nov. 12 1929 UNITED STATES PATENT OFFICE JULIUS WEINBERGE R, OF NEW YORK, N. Y., ASSIGINOR T RADIO CORPORATION 01! AMERICA, A CORPORATION OF DELAWARE ELECTRICAL DISTRIBUTION SYSTEM Application filed August 17, 1923. Serial No. 657,859.

In electrical distribution systems, in which a generator is connected to one or more energy consuming devices, it is sometimes desirable to be able to connect or disconnect any 6 number of these devices and at all times maintain a constant energy load on the generator This is, for example, the case in a distribution system in which a vacuum tube amplifier or oscillator feeds alternating cur- 10 rents to a number of energy consuming circuits or devices, such as telephones or loud speakers. Every vacuum tube has a socalled optimum impedance, which corresponds to-the internal resistance of a generator, and will produce its maximum energy output when the impedance of the load is equal to the impedance of the tube. When a distribution system is connected to a tube,

and the combined load impedance adjusted so as to give an impedance equal to that of the tube, maximum output will be obtained;-

certain voltages and currents will then exist in the distribution system. However, if any of the energy absorbing devices are now disconnected, or more connected on, the currents through all the other devices will be changed.

The latter efl'ect is undesirable; for example,

if a vacuum tube amplifier is feeding a number of loud speakers, and some of these are disconnected, the others may then suddenly increase in loudness, which is quite objectionable to the listeners, or which may result in overloading of the loud speakers with conse uent distortion.

t is the object of this invention to provide a system whereby constant load on the generator, and therefore constant currents throughout the distribution system, is maintained. This is accomplished by providing along with each energy consuming device, an energy consuming system which duplicates it in electrical constants, but 'not necessarily in its construction or function; and arranging a switching system whereby when each regular energy consuming device is cut out of circuit, the duplicate evice. or system is substituted for it. To make this clearer, let us consider the vacuum tube amplifier-loud speaker system mentioned above. Each loud speaker would have provided along with it an electrical network composed of capacities, inductances and resistances, which would be connected to a switch, the loud speaker itself being also connected to this same switch, and

the switch so arranged that when the loud range of frequencies equal to that displayed by the loudspeaker windings, will be suflicient.

It will be noted that a distinguishing feature of the invention is the substitution of an electrical network having an electrical behavior equivalent to that of the actual energy consuming device, but not having the same function. For example, the function of a loud speaker is to convert electrical en ergy into sound waves; its electrical behavior is determined by the constants of its windings, and to some extent by reaction of me chanically vibrating parts on the constants of these windings (as inthe case of the back E. M. F. due to a rotating motor armature). However, all the electrical constants of a loud speaker can be duplicated by a network of capacities, inductances and resistances, without the consequent production of sound. Here we have a case of electrical duplication of a device without duplication of function.

The single figure of the drawing is a diagram of a system according to the invention.

In the illustrated system 1 is a vacuum tube amplifier, having input and output trans formers 2 and 3 respectively. Across the terminals of the output transformer'are connected'bus-bars, 4. These bus-bars are then connected to the center posts of double pole double throw switches, 5. To the posts on one side of the switches are connected loud speakers 6, and to those on the other side inductances, 7, and resistances 8, the latter forming an impedance substantially'equal to that of the loud speaker. A system such as this may have a vacuum tube of internal resistance equal to 5000. ohms each loud speaker may have an inductance of 4: henrys (reactance=20,000 ohms at 800 cycles) and an effective resistance of 8000 ohms at 800 cycles, An inductance of 4i henrys in series with a resistance of 8000 ohms may then be substituted for the loud speaker, as an approximately equivalent circuit, or one having an iron core may be so designed that its efiective resistance will vary in the same manner with frequency as the efiective resistance of the loud speaker, thus more closely approximating the impedance of the latter over a range of frequencies. The output transformer of the tube will be made with a ratio such that the impedance of the entire energyiconsuming system is transferred back into the plate circuit of the tube as an impedance equal to the optimum impedance (sometimes termed internal resistance) of the tube. F or example, if there are 20 loud speakers in the system, each with the above constants, each loud speaker will have an impedance oi 21500 ohms at 800 cycles, and 20 loud speakers in parallel will have an impedance of 1075 ohms. If the tube has an output impedance of 5000 ohms, the transformer will be made so that the square of its ratio, stepping down from the tube to the distribution system, is equal to the quotient of 5000 divided. by 10755 or, its ratio will be made 2.16.

it is obvious that the same principle can be applied whether the energy consuming devices are connected in parallel, series or in any other manner; and that it is not limited to the specific instance cited above.

having described my invention what I claim is as follows:

1. In combination an amplifier, having input and output circuits, one or more loud speakers arrangedso as to be connected to'the output circuit, one or more electrical energy consuming devices each having substantially the same electrical constants as each of the loud speakers, and-switching means for connecting either a loud speaker or its electrically equivalent network to the output circuit of the amplifier.

2. In combination, an. amplifier having an output circuit, translation means in the cuput circuit having resistance, power and inmeans output distribution network, an electrical consuming device comprising a loud speaker connected to the network, another electrical energy consuming device substantially duplicating the first mentioned device in electrical constants but not in function, and switching means for introducing the duplicate device into the network as an energy consumer in place of the loudspeaker.

4. Ina radio receiving system, an amplifier having an input and an output circuit, a plurality of loudspeakers connected in said output circuit, an equivalent number of separate energy consuming devices adapted to be connected in said output circuit and arranged so that each loudspeaker has associated therewith one of said energy consuming devices, each of said devices being adapted to substantially duplicate the loudspeaker associated therewith in electrical constants but not in function and individual switching means for introducing any one of said duplicating devices into the network as an energy consumer in place of its associated louds eaker.

JULIUS WEINBER ER.

ductive components,switches in the output I circuit in one position for connecting both sides of the circuit to the translating means, said switches inanother position for disconnecting the translating means and connecting both sides of the circuit to other cirnents of the translatin cuits havingresistance components equal to the combined power and resistance compomeans and inductive components equal to t e inductive components of the translating means, whereby when the translating means is disconnected unbalance er load on the amplifier is prevented 3. In combination a vacuum tube amplifier having input and output circuits, an 

